Effects of chronic cigarette smoking on canine arteries.

Segments of carotid and femoral arteries were obtained from beagles subjected to cigarette smoking (12/day for 2 yr) and from unexposed controls. The segments were used for in vitro studies of active and passive mechanics, dose responses to norepinephrine (NE) and K+, connective tissue content, and water and electrolyte content and distribution. No significant differences in passive arterial wall mechanics or geometry at 100 mmHg were found, but a small (significant) increase in passive stiffness was found at wall loads corresponding to higher values of pressure for arteries from smokers. No significant changes in connective tissue composition were found at either site. No significant differences in maximum active force development were found at either site between the two groups. However, values of active force near the middle of the active force-length curve were lower (P less than 0.05) for smoker's arteries when expressed as a fraction of the maximum developed force. No differences in cell volume were found in arteries from the two groups. Mg2+ and K+ content of the femoral and Ca2+ content of both arteries were greater in the smokers. No difference in NE dose-response relations were found for either site. A statistically significant decrease in responsiveness to K+ was found for femoral arteries from smokers, but not for the carotids. The results of these studies demonstrate that some significant changes in arterial wall properties occur in beagle dogs exposed to chronic cigarette smoke.